Rotary hammer



Jan. 20, 1931. N, P RlDGwAY '1,789,712

ROTARY HAMMER Filed May 19, 1926 gallglglllllrlllllll /A lil-"11111111 2 gezag INVENToR /YEL50/v PED/06mm 4 30 tion.

Patented Jan. 2o, 1931 UNITED, STATES PlvrlazNrT,'o1-'Flesl maLsoNr.` RIDGWAY, oF TACOMA, WASHINGTON ROTARY HAMMER. f

Appunti@ nlednay 19, 1926. serial no. "116,139.`

This invention relates to rotary hammers, and the principal object of the invention residing in the provision of air cushions for checking the rebound of the hammers after i 6 they have struck the tool and for retarding the return of the hammers into striking position so as to reduce vibration, and shock and thereby provide afmore durable and more easily handled device.

A further object of the invention is to con* nect the cylinders wherein the hammers are Y contained by means of an air tube so that the rebound of thevhammer in one cylinder will drive air into the cylinder'containing the other hammer to force, the latter hammer into striking position.

Otherobjects reside in the various details of construction and combination of parts as will be fully described in the following specification.

Figure 2 is a horizontal, sectional view taken on the line 2 2 in Figure 1.

Figure 3 is a sectional View taken on line 3-3 in Figure 1.

Referring more in detail to the drawlngs- Y 1 designates an enclosing housing made up of opposite side sections 2 and 3 that are joined by means of a plurality of bolts l exthe 4 tended through the peripheries of the sections and through an interposed spacing ring 5. At one side of the casing is an extension 6 in which a tubular bushing 7 is fixed by means of al set screw 8; the bushing slidably containing the shank 9 of a riveting tool, drill bit, or other instrument, designated. at 10, that may be operated by the striking of blows in rapid succession against its inner end.

Extending centrally through the housing is anoperating shaft 11 supported'lrotatably Y y by ball bearings 12fco11tained inb'all races formed in collarslthat are fixed on the shaft, and in annular bearings 14 thatv are fixed to the sections 2 and 3 forming the opposite sides of the housing.: Driving cony f nection maybe made with either end of the Y shaft 11 by any suitable means, such as a flexibleshaft.. F ixedon the shaft 11, in `a plane that is perpendicular thereto and centrally between Y the sides ofthe housing, "is a rectangular `plate 15 that forms the hammer'body. Fixed in parallelrelation to opposite edges'of the plate are cylinders 16 in "which hammers 17 are slidably fittedeach hammer being provided at its outer end .withfa reduced, impact shank 17A that extends slidably through the outer end wall of its cylinder. During v operation of the device, the hammer elements are lmoved byv centrifugal force to theouter ends of their cylinders intol positions at which the ends fof the Shanks 17Av will be causedto impact with the inner end of the l y mounting shank lof the 'tool'10`so as to effect the hammering operation..` The cylinders 16 are so mounted that the axial line of the hammers and the axial line of the shankof the-tool will practically coincide. at the time of the impact. 1

The inner end of the cylindersl are closed by caps 18 to provide closed air chambers 19 at the inner ends of the hammer elements. Each cap is provided with aball chamber 20 opening directly into the chamber 19 and these chambers 2O are connected by means of al tube 30'through which air compressed and displaced by vinward movement of the hammer in one cylinder may be forced into the chamber 19 of the other cylinder to drive its hammer element outwardly'into impactposition. Valve ports 21 are provided in the outer jends of the ball chambers and'ball checks 22- are contained in the chambers to close these ports during inward travel of the hammers 9 butV which open to admit airy as the hammers 1 move outwardly.

As a means of retarding' the outward throw of the hammer elements bycentrifugal force after impact and rellmund7 I have provided Y for trapping air between the outer ends oi' the .designated atQ, 'within the louter end walls y of the cylinders. After a hammer element A' has been brought into impact with the shank 7 of the `tool and has rebounded, it will be' moved outwardly again by the forcing of airv into the end of .its cylinder through tube 30 Y and also due to the centrifugal forcev inc i 'dental to rapid rotation ofthe de-vic'e'andfas it moves outwardly in its cylinder the trapped air invpocket 28 retards its movement so that it moves easily into position and does not strike with considerable force against the end wall. oi the cylinder' and thereby. causevjolt, vibration vand ultimate self destructionf VhileY the tube connection 30 is not absolutely necessary to effective, satisfactory operation of the hammer elements where they Y are .so disposed that centrifugal force will return them to impact position, it is desirable inV machines Wherethe hammers are of such length that centrifugalforce is minimized to such an extent, that it can .not be depended upon to return them. j l A handleoil suitable character, such as is shown' at 85, may be provided forholding the device when in use and this may be fixed between the opposite sides of the housing, as is shown in Figure 1.

' Y With thedevice so constructed, the jolt and Aj ar of operation is reduced to a minimum and a more satisfactory and longer lived tool is provided. s I

. Having thus described my invention, what I claim as new therein-and desire to secure by Letters-Patent, is: v -v e y 'LA hammer comprising ay rotating ham- V mer body, a pair of cylinders Afixed in yparallel rela-tion to opposite edges of the said body,

hammer elements slida-bly fitted in said cylinders and having impac't sha-nks extending from their outer ends through the outer end walls of the cylinders, and a tube connecting the inner ends of the cylinders through which air may be driven from one cylinder due to reboundoithe hammer therein into the other cylinder to move its hammer out to impact position.

Q. A hammer comprising a housing mounting a drillbit or thevlilre, a hammer body otatably mounted in the housing and having a drivingfshaft, a pair of cylinders iixed in parallel` relationl to vopposite edges of the bony, hammer eiements slidablyfitted in said cylinders, each having an impact shank of reduced diameter extending rtherefrom Ythrough the outer end of its cylinder into position for impact with the said drill bit, said cylinders: providing air cushions at oppositeends of the hammer elements, and a tube connectingv the inner ends ot the two cylinders.

3. A hammer comprising a rotating ham- Signed'at Tacoma, Washington, this 30th day of March, 1926.

`NnLsoN P, RIDGWAY.

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